1. Field of the Invention
Gasoline compositions are highly refined products. Despite this, they contain minor amounts of impurities which can promote corrosion during the period that the fuel is transported in bulk or held in storage. Corrosion can also occur in the fuel tank, fuel lines and carburetor of a motor vehicle. As a result, a commercial motor fuel composition must contain a corrosion inhibitor to inhibit or prevent corrosion.
In the normal operation of a carburetted internal-combustion engine, a build-up of gasoline insoluble deposits occurs around the throttle plate and throat of the carburetor. The unchecked buildup of these deposits can disturb the efficient metering of fuel to the engine, and may lead to excessive fuel consumption or uneven engine operation, particularly when the engine is running at idle. For this reason, a commercial motor fuel composition must contain a small quantity of a carburetor detergent to keep carburetors operating at maximum efficiency.
An acceptable motor fuel contains additives to correct or inhibit these disabling characteristics of motor fuel. Thus, the discovery of novel and compatible motor fuel additives capable of general application and selective modification to accomodate changing demands while combining good detergency properties with effective corrosion inhibition will provide a material advance in the state of the art.
It has been discovered that several novel reaction products, prepared by a combination of Knoevenagel and Michael reactions, impart improved carburetor detergency to unleaded gasoline. In addition, we have found that these reaction products afford corrosion resistance to automotive fuel systems when blended in unleaded fuels.
2. Description of the Prior Art
In "Potassium Fluoride Catalyzed Reactions Between Malonitrile and Alpha, Beta-Unsaturated Ketones", 48 CANADIAN JOURNAL OF CHEMISTRY, 3064 (1970), ApSimon et al discloses that steric factors affect which competing reaction, the Michael addition or the Knoevenagel condensation, occurs in particular chemical processes.
In "A Novel Thermal Knoevenagel Condensation via a Thermal Michael Reaction", 10 (11) SYNTHETIC COMMUNICATIONS 843-850 (1980) Afzal et al discloses the scope, limitation and mechanism of a Knoevenagel condensation reaction which occurs via a Thermal Michael reaction.